1. Field of the Invention
The present invention relates to a device mounting board and a manufacturing method therefor, a semiconductor module and a mobile apparatus carrying the same.
2. Description of the Related Art
In recent years, with miniaturization and higher performance in electronic devices, demand has been ever greater for further miniaturization of semiconductor devices used in the electronic devices. With such miniaturization of semiconductor devices, it is of absolute necessity that the pitch of electrodes to enable mounting on a wiring board be made narrower. A known method of surface-mounting a semiconductor device is flip-chip mounting in which solder balls are formed on electrodes of the semiconductor device and the solder balls are soldered to an electrode pad of the wiring board. With this flip-chip method, however, there are restrictive factors for the narrowing of the pitch of electrodes, such as the size of the solder ball itself and the bridge formation at soldering. As one structure used to overcome these limitations, known is a structure where a bump structure formed by half-etching a substrate is used as an electrode or a via, and the electrodes of the semiconductor device are connected to the bump structure by mounting the semiconductor device on the substrate with an insulating resin layer, such as epoxy resin, held between the semiconductor device and the substrate.
On the other hand, a semiconductor device is known where an electrode exposed in an opening formed in an insulating layer is provided. In this semiconductor device, a side wall of the insulating layer is located around the electrode.
In such a case of the aforementioned conventional practice where a bump electrode is connected to the semiconductor device where the side wall of the insulating layer is located around the electrode, the insulation layer around the electrode in a semiconductor device side may be an obstacle if the position of the bump electrode is displaced against the electrode in the semiconductor device side. If the position thereof is displaced, there may be cases where the electrode in the semiconductor device side does not come in contact with the bump electrode. To prevent this, the position of the semiconductor-device-side electrode and the bump electrode needs to be done more accurately. As a result, the manufacturing of semiconductor modules becomes more complex and the manufacturing cost increases.